// Copyright 2015 gRPC authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

#include <grpc/impl/propagation_bits.h>
#include <grpc/slice.h>
#include <grpc/status.h>
#include <grpc/support/time.h>

#include <algorithm>
#include <memory>
#include <string>

#include "absl/log/check.h"
#include "absl/log/log.h"
#include "absl/status/statusor.h"
#include "src/core/lib/iomgr/port.h"

// This test won't work except with posix sockets enabled
#ifdef GRPC_POSIX_SOCKET_EV

#include <grpc/credentials.h>
#include <grpc/grpc.h>
#include <grpc/grpc_security.h>
#include <grpc/support/alloc.h>
#include <string.h>

#include <vector>

#include "absl/strings/str_format.h"
#include "absl/strings/str_join.h"
#include "absl/strings/str_split.h"
#include "absl/strings/string_view.h"
#include "src/core/lib/event_engine/tcp_socket_utils.h"
#include "src/core/lib/event_engine/utils.h"
#include "src/core/lib/iomgr/socket_utils_posix.h"
#include "src/core/util/host_port.h"
#include "test/core/end2end/cq_verifier.h"
#include "test/core/test_util/port.h"
#include "test/core/test_util/test_config.h"

// This test exercises IPv4, IPv6, and dualstack sockets in various ways.

using grpc_event_engine::experimental::EventEngine;

static absl::StatusOr<std::unique_ptr<EventEngine::DNSResolver>> ee_resolver;

static void drain_cq(grpc_completion_queue* cq) {
  grpc_event ev;
  do {
    ev = grpc_completion_queue_next(
        cq, grpc_timeout_milliseconds_to_deadline(5000), nullptr);
  } while (ev.type != GRPC_QUEUE_SHUTDOWN);
}

static void log_resolved_addrs(const char* label, const char* hostname) {
  if (!ee_resolver.ok()) {
    return;
  }
  absl::StatusOr<std::vector<EventEngine::ResolvedAddress>> addresses =
      grpc_event_engine::experimental::LookupHostnameBlocking(
          ee_resolver->get(), hostname, "80");
  if (!addresses.ok()) {
    LOG(ERROR) << "Failed to lookup hostname: " << hostname
               << ", status: " << addresses.status();
    return;
  }
  for (const auto& addr : *addresses) {
    LOG(INFO)
        << label << ": "
        << grpc_event_engine::experimental::ResolvedAddressToURI(addr)->c_str();
  }
}

void test_connect(const char* server_host, const char* client_host, int port,
                  int expect_ok) {
  grpc_channel* client;
  grpc_server* server;
  grpc_completion_queue* cq;
  grpc_call* c;
  grpc_call* s;
  gpr_timespec deadline;
  int got_port;
  grpc_op ops[6];
  grpc_op* op;
  grpc_metadata_array initial_metadata_recv;
  grpc_metadata_array trailing_metadata_recv;
  grpc_metadata_array request_metadata_recv;
  grpc_status_code status;
  grpc_call_error error;
  grpc_slice details;
  int was_cancelled = 2;
  grpc_call_details call_details;
  char* peer;
  int picked_port = 0;

  if (port == 0) {
    port = grpc_pick_unused_port_or_die();
    picked_port = 1;
  }

  std::string server_hostport = grpc_core::JoinHostPort(server_host, port);

  grpc_metadata_array_init(&initial_metadata_recv);
  grpc_metadata_array_init(&trailing_metadata_recv);
  grpc_metadata_array_init(&request_metadata_recv);
  grpc_call_details_init(&call_details);

  // Create server.
  cq = grpc_completion_queue_create_for_next(nullptr);
  server = grpc_server_create(nullptr, nullptr);
  grpc_server_register_completion_queue(server, cq, nullptr);
  grpc_server_credentials* server_creds =
      grpc_insecure_server_credentials_create();
  CHECK((got_port = grpc_server_add_http2_port(server, server_hostport.c_str(),
                                               server_creds)) > 0);
  grpc_server_credentials_release(server_creds);
  if (port == 0) {
    port = got_port;
  } else {
    CHECK_EQ(port, got_port);
  }
  grpc_server_start(server);
  grpc_core::CqVerifier cqv(cq);

  // Create client.
  std::string client_hostport;
  if (client_host[0] == 'i') {
    // for ipv4:/ipv6: addresses, concatenate the port to each of the parts
    std::vector<absl::string_view> uri_parts =
        absl::StrSplit(client_host, ',', absl::SkipEmpty());
    std::vector<std::string> hosts_with_port;
    hosts_with_port.reserve(uri_parts.size());
    for (const absl::string_view& uri_part : uri_parts) {
      hosts_with_port.push_back(absl::StrFormat("%s:%d", uri_part, port));
    }
    client_hostport = absl::StrJoin(hosts_with_port, ",");
  } else {
    client_hostport = grpc_core::JoinHostPort(client_host, port);
  }
  grpc_channel_credentials* creds = grpc_insecure_credentials_create();
  client = grpc_channel_create(client_hostport.c_str(), creds, nullptr);
  grpc_channel_credentials_release(creds);

  LOG(INFO) << "Testing with server=" << server_hostport.c_str()
            << " client=" << client_hostport.c_str() << " (expecting "
            << (expect_ok ? "success" : "failure") << ")";
  log_resolved_addrs("server resolved addr", server_host);
  log_resolved_addrs("client resolved addr", client_host);

  if (expect_ok) {
    // Normal deadline, shouldn't be reached.
    deadline = grpc_timeout_milliseconds_to_deadline(60000);
  } else {
    // Give up faster when failure is expected.
    // BUG: Setting this to 1000 reveals a memory leak (b/18608927).
    deadline = grpc_timeout_milliseconds_to_deadline(8000);
  }

  // Send a trivial request.
  grpc_slice host = grpc_slice_from_static_string("foo.test.google.fr");
  c = grpc_channel_create_call(client, nullptr, GRPC_PROPAGATE_DEFAULTS, cq,
                               grpc_slice_from_static_string("/foo"), &host,
                               deadline, nullptr);
  CHECK(c);

  memset(ops, 0, sizeof(ops));
  op = ops;
  op->op = GRPC_OP_SEND_INITIAL_METADATA;
  op->data.send_initial_metadata.count = 0;
  op->flags = expect_ok ? GRPC_INITIAL_METADATA_WAIT_FOR_READY : 0;
  op->reserved = nullptr;
  op++;
  op->op = GRPC_OP_SEND_CLOSE_FROM_CLIENT;
  op->flags = 0;
  op->reserved = nullptr;
  op++;
  op->op = GRPC_OP_RECV_INITIAL_METADATA;
  op->data.recv_initial_metadata.recv_initial_metadata = &initial_metadata_recv;
  op->flags = 0;
  op->reserved = nullptr;
  op++;
  op->op = GRPC_OP_RECV_STATUS_ON_CLIENT;
  op->data.recv_status_on_client.trailing_metadata = &trailing_metadata_recv;
  op->data.recv_status_on_client.status = &status;
  op->data.recv_status_on_client.status_details = &details;
  op->flags = 0;
  op->reserved = nullptr;
  op++;
  error = grpc_call_start_batch(c, ops, static_cast<size_t>(op - ops),
                                grpc_core::CqVerifier::tag(1), nullptr);
  CHECK_EQ(error, GRPC_CALL_OK);

  if (expect_ok) {
    // Check for a successful request.
    error = grpc_server_request_call(server, &s, &call_details,
                                     &request_metadata_recv, cq, cq,
                                     grpc_core::CqVerifier::tag(101));
    CHECK_EQ(error, GRPC_CALL_OK);
    cqv.Expect(grpc_core::CqVerifier::tag(101), true);
    cqv.Verify();

    memset(ops, 0, sizeof(ops));
    op = ops;
    op->op = GRPC_OP_SEND_INITIAL_METADATA;
    op->data.send_initial_metadata.count = 0;
    op->flags = 0;
    op++;
    op->op = GRPC_OP_SEND_STATUS_FROM_SERVER;
    op->data.send_status_from_server.trailing_metadata_count = 0;
    op->data.send_status_from_server.status = GRPC_STATUS_UNIMPLEMENTED;
    grpc_slice status_details = grpc_slice_from_static_string("xyz");
    op->data.send_status_from_server.status_details = &status_details;
    op->flags = 0;
    op++;
    op->op = GRPC_OP_RECV_CLOSE_ON_SERVER;
    op->data.recv_close_on_server.cancelled = &was_cancelled;
    op->flags = 0;
    op++;
    error = grpc_call_start_batch(s, ops, static_cast<size_t>(op - ops),
                                  grpc_core::CqVerifier::tag(102), nullptr);
    CHECK_EQ(error, GRPC_CALL_OK);

    cqv.Expect(grpc_core::CqVerifier::tag(102), true);
    cqv.Expect(grpc_core::CqVerifier::tag(1), true);
    cqv.Verify();

    peer = grpc_call_get_peer(c);
    VLOG(2) << "got peer: '" << peer << "'";
    gpr_free(peer);

    CHECK_EQ(status, GRPC_STATUS_UNIMPLEMENTED);
    CHECK_EQ(grpc_slice_str_cmp(details, "xyz"), 0);
    CHECK_EQ(grpc_slice_str_cmp(call_details.method, "/foo"), 0);
    CHECK_EQ(grpc_slice_str_cmp(call_details.host, "foo.test.google.fr"), 0);
    CHECK_EQ(was_cancelled, 0);

    grpc_call_unref(s);
  } else {
    // Check for a failed connection.
    cqv.Expect(grpc_core::CqVerifier::tag(1), true);
    cqv.Verify();

    LOG(INFO) << "status: " << status
              << " (expected: " << GRPC_STATUS_UNAVAILABLE << ")";
    CHECK_EQ(status, GRPC_STATUS_UNAVAILABLE);
  }

  grpc_call_unref(c);

  // Destroy client.
  grpc_channel_destroy(client);

  // Destroy server.
  grpc_server_shutdown_and_notify(server, cq, grpc_core::CqVerifier::tag(1000));
  grpc_event ev;
  do {
    ev = grpc_completion_queue_next(cq, grpc_timeout_seconds_to_deadline(5),
                                    nullptr);
  } while (ev.type != GRPC_OP_COMPLETE ||
           ev.tag != grpc_core::CqVerifier::tag(1000));

  grpc_server_destroy(server);
  grpc_completion_queue_shutdown(cq);
  drain_cq(cq);
  grpc_completion_queue_destroy(cq);

  grpc_metadata_array_destroy(&initial_metadata_recv);
  grpc_metadata_array_destroy(&trailing_metadata_recv);
  grpc_metadata_array_destroy(&request_metadata_recv);

  grpc_call_details_destroy(&call_details);
  grpc_slice_unref(details);
  if (picked_port) {
    grpc_recycle_unused_port(port);
  }
}

int external_dns_works(const char* host) {
  if (!ee_resolver.ok()) {
    return 0;
  }
  absl::StatusOr<std::vector<EventEngine::ResolvedAddress>> addresses =
      grpc_event_engine::experimental::LookupHostnameBlocking(
          ee_resolver->get(), host, "80");
  if (!addresses.ok()) {
    return 0;
  }
  int result = 1;
  for (const auto& addr : *addresses) {
    // Kokoro on Macservice uses Google DNS64 servers by default
    // (https://en.wikipedia.org/wiki/Google_Public_DNS) and that breaks
    // "dualstack_socket_test" due to loopback4.unittest.grpc.io resolving to
    // [64:ff9b::7f00:1]. (Working as expected for DNS64, but it prevents the
    // dualstack_socket_test from functioning correctly). See b/201064791.
    if (grpc_event_engine::experimental::ResolvedAddressToURI(addr).value() ==
        "ipv6:%5B64:ff9b::7f00:1%5D:80") {
      LOG(INFO) << "Detected DNS64 server response. Tests that depend on "
                   "*.unittest.grpc.io. will be skipped as they won't work "
                   "with DNS64.";
      result = 0;
      break;
    }
  }
  return result;
}

int main(int argc, char** argv) {
  int do_ipv6 = 1;

  grpc::testing::TestEnvironment env(&argc, argv);
  grpc_init();

  if (!grpc_ipv6_loopback_available()) {
    LOG(INFO) << "Can't bind to ::1.  Skipping IPv6 tests.";
    do_ipv6 = 0;
  }

  ee_resolver =
      grpc_event_engine::experimental::GetDefaultEventEngine()->GetDNSResolver(
          grpc_event_engine::experimental::EventEngine::DNSResolver::
              ResolverOptions());
  if (!ee_resolver.ok()) {
    LOG(ERROR) << "Failed to get EventEngine DNSResolver: "
               << ee_resolver.status();
  }

  // For coverage, test with and without dualstack sockets.
  for (grpc_forbid_dualstack_sockets_for_testing = 0;
       grpc_forbid_dualstack_sockets_for_testing <= 1;
       grpc_forbid_dualstack_sockets_for_testing++) {
    // :: and 0.0.0.0 are handled identically.
    test_connect("::", "127.0.0.1", 0, 1);
    test_connect("::", "::ffff:127.0.0.1", 0, 1);
    test_connect("::", "ipv4:127.0.0.1", 0, 1);
    test_connect("::", "ipv6:[::ffff:127.0.0.1]", 0, 1);
    test_connect("::", "localhost", 0, 1);
    test_connect("0.0.0.0", "127.0.0.1", 0, 1);
    test_connect("0.0.0.0", "::ffff:127.0.0.1", 0, 1);
    test_connect("0.0.0.0", "ipv4:127.0.0.1", 0, 1);
    test_connect("0.0.0.0", "ipv4:127.0.0.1,127.0.0.2,127.0.0.3", 0, 1);
    test_connect("0.0.0.0", "ipv6:[::ffff:127.0.0.1],[::ffff:127.0.0.2]", 0, 1);
    test_connect("0.0.0.0", "localhost", 0, 1);
    if (do_ipv6) {
      test_connect("::", "::1", 0, 1);
      test_connect("0.0.0.0", "::1", 0, 1);
      test_connect("::", "ipv6:[::1]", 0, 1);
      test_connect("0.0.0.0", "ipv6:[::1]", 0, 1);
    }

    // These only work when the families agree.
    test_connect("127.0.0.1", "127.0.0.1", 0, 1);
    test_connect("127.0.0.1", "ipv4:127.0.0.1", 0, 1);
    if (do_ipv6) {
      test_connect("::1", "::1", 0, 1);
      test_connect("::1", "127.0.0.1", 0, 0);
      test_connect("127.0.0.1", "::1", 0, 0);
      test_connect("::1", "ipv6:[::1]", 0, 1);
      test_connect("::1", "ipv4:127.0.0.1", 0, 0);
      test_connect("127.0.0.1", "ipv6:[::1]", 0, 0);
    }

    if (!external_dns_works("loopback4.unittest.grpc.io") ||
        !external_dns_works("loopback46.unittest.grpc.io")) {
      LOG(INFO) << "Skipping tests that depend on *.unittest.grpc.io.";
    } else {
      test_connect("loopback46.unittest.grpc.io", "loopback4.unittest.grpc.io",
                   0, 1);
      test_connect("loopback4.unittest.grpc.io", "loopback46.unittest.grpc.io",
                   0, 1);
      if (do_ipv6) {
        test_connect("loopback46.unittest.grpc.io",
                     "loopback6.unittest.grpc.io", 0, 1);
        test_connect("loopback6.unittest.grpc.io",
                     "loopback46.unittest.grpc.io", 0, 1);
        test_connect("loopback4.unittest.grpc.io", "loopback6.unittest.grpc.io",
                     0, 0);
        test_connect("loopback6.unittest.grpc.io", "loopback4.unittest.grpc.io",
                     0, 0);
      }
    }
  }

  grpc_shutdown();

  return 0;
}

#else  // GRPC_POSIX_SOCKET_EV

int main(int argc, char** argv) { return 1; }

#endif  // GRPC_POSIX_SOCKET_EV
